OPA657
OPA
657
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SBOS197E – DECEMBER 2001 – REVISED DECEMBER 2008
1.6GHz, Low-Noise, FET-Input
OPERATIONAL AMPLIFIER
FEATURES
DESCRIPTION
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The OPA657 combines a high gain bandwidth, low distortion,
voltage-feedback op amp with a low voltage noise JFET-input
stage to offer a very high dynamic range amplifier for high
precision ADC (Analog-to-Digital Converter) driving or wideband
transimpedance applications. Photodiode applications will see
improved noise and bandwidth using this decompensated,
high gain bandwidth amplifier.
HIGH GAIN BANDWIDTH PRODUCT: 1.6GHz
HIGH BANDWIDTH 275MHz (G = +10)
LOW INPUT OFFSET VOLTAGE: ±0.25mV
LOW INPUT BIAS CURRENT: 2pA
LOW INPUT VOLTAGE NOISE: 4.8nV/ Hz
HIGH OUTPUT CURRENT: 70mA
FAST OVERDRIVE RECOVERY
Very low level signals can be significantly amplified in a single
OPA657 gain stage with exceptional bandwidth and accuracy.
Having a high 1.6GHz gain bandwidth product will give
> 10MHz signal bandwidths up to gains of 160V/V (44dB). The
very low input bias current and capacitance will support this
performance even for relatively high source impedances.
APPLICATIONS
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WIDEBAND PHOTODIODE AMPLIFIER
WAFER SCANNING EQUIPMENT
ADC INPUT AMPLIFIER
TEST AND MEASUREMENT FRONT END
HIGH GAIN PRECISION AMPLIFIER
Broadband photodetector applications will benefit from the low
voltage noise JFET inputs for the OPA657. The JFET input
contributes virtually no current noise while for broadband
applications, a low voltage noise is also required. The low
4.8nV/ Hz input voltage noise will provide exceptional input
sensitivity for higher bandwidth applications. The example
shown below will give a total equivalent input noise current of
1.8pA/ Hz over a 10MHz bandwidth.
RELATED OPERATIONAL AMPLIFIER PRODUCTS
200kΩ TRANSIMPEDANCE BANDWIDTH
116
Transimpedance Gain (dB)
10MHz Bandwidth
DEVICE
106
SLEW VOLTAGE
VS BW RATE NOISE
(V) (MHz) (V/µS) (nV/√HZ) AMPLIFIER DESCRIPTION
OPA355 +5
OPA655 ±5
OPA656 ±5
OPA627 ±15
THS4601 ±15
96
86
200
400
500
16
180
300
290
170
55
100
5.80
6
7
4.5
5.4
Unity-Gain
Unity-Gain
Unity-Gain
Unity-Gain
Unity-Gain
Stable
Stable
Stable
Stable
Stable
CMOS
FET-Input
FET-Input
FET-Input
FET-Input
0.1pF
76
200kΩ
66
100kHz
1MHz
10MHz
50MHz
Frequency
λ
OPA657
VO
(12pF)
–Vb
Wideband Photodiode Transimpedance Amplifier
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
Copyright © 2001-2008, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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